Gripping dies for pipe tongs and the like



Oct. 11, 1955 N. s. WOOLLEY GRIPPING DI s FOR PIPE TONGS AND THE LIKE .viv i Vivi vi 0 Filed May 25, 1953 r mm n wx h IN V EN TOR.

United States Patent 2,720,128 GRIPPING DIES FOR PIPE TONGS AND THE LIKE Ned S. Woolley, Odessa, Tex. Application May 25, 1953, Serial No. 357,162

12 Claims. (Cl. 81-186) This invention relates to new and useful improvements in gripping dies and relates particularly to dies which are employed in pipe tongs.

As is well known, dies of this character ordinarily comprise a bar or body section having a gripping face, and said bar or section is insertable within grooves, usually dove-tail in cross-section, provided in the tong or gripping device. The die bar or body section has a tight driving fit within the retaining groove, and it is usual practice to insert and remove the die by applying hammer blows thereto. However, because the gripping face which includes gripping teeth has been treated to a high degree of hardness, the corners of the die are brittle and are likely to chip under the hammer blows with the flying particles creating a considerable hazard to the tool operator manipulating the hammer.

Some attempts have been made to reduce the hazard incident to driving a die into position within a tong or gripping device by making the end of the die of soft material as compared to the work-hardened surface and examples of such attempts are the prior patents to Weiss, 2,596,880, and Barnard, 2,609,720. The soft ended dies have been found to eliminate the hazard incident to chipping when the die is driven in place, but since the die must also be driven from its groove, the soft end of the die creates a disadvantage in that the die becomes so tightly bound in the groove that it cannot be removed. Because the groove which receives the die is narrow, the die cannot be driven out by a hammer alone and usually a chisel, small rod or the like is employed for this purpose. Obviously, such chisel or small rod must necessarily engage the soft upper end of the die and upon receiving hammer blows tends to spread or deform the soft end outwardly so that the frictional hold of the die within is increased; continued hammering only results in tighter wedg ing of the die within the groove, and in many instances the entire tool must be taken into a shop to remove the die by grinding or cutting out.

Another major disadvantage of the dies now in general use is that the gripping teeth thereof are normally arranged in alignment transversely of the gripping face of the die. Thus, the grooves between adjacent transverse rows of teeth extend in a plane normal to the longitudinal axis of the die, and when the teeth engage the pipe surface the plane of engagement is in the plane of the trans verse rows of teeth, with no gripping ever occurring in the open area between tooth rows which open area is formed by the transverse grooves between adjacent rows. With this usual arrangement of the gripping teeth, any slippage of the die while in engagement with the pipe results in a scoring of the pipe because each tooth of each transverse row follows or is in alignment with the adja cent tooth and actually engages the same pipe area which was engaged by the preceding tooth.

It is one object of this invention to provide an improved die for tongs or pipe-gripping devices which will overcome the disadvantages incident to a soft-end die and which has an improved tooth construction producing 2,720,128 Patented Och 11, 1955 increased gripping action and eliminating undue scoring of the outer surface of the pipe being gripped.

An important object of the invention is to provide an improved die for pipe-gripping devices wherein the die has its outer surface heat treated to a high degree of hardness and wherein the corners of the die are ground 01f to expose the softer material of the die body, whereby the die may be driven into position within a receiving groove without the likelihood of chipping and also whereby the die may be removed from said groove without deforming the die end and thereby wedging said die within the groove.

Another object of the invention is to provide a die of the character described, wherein the teeth on the gripping face of the die are arranged in staggered relationship in a plane transversely of the face of the die, whereby scoring of the pipe by reason of slippage of the die is minimized.

A further object is to provide a die for a pipe-gripping device, wherein a plurality of tooth rows are arranged longitudinally of the die with each tooth being substantially conical in cross-section, together with spaced grooves which are cut obliquely across the longitudinal tooth rows to thereby dispose the individual teeth in alternate or staggered relationship in a plane transversely of the die.

The construction designed to carry out the invention will be hereinafter described together with other features thereof. i

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown, and wherein:

Fig. l is an isometric view of a pipe tong having a die constructed in accordance with the invention mounted therein;

Fig. 2 is an isometric view of one of the jaws of the tong showing the die being inserted therein;

Fig. 3 is a face view of the tong die constructed in accordance with the invention;

Fig. 4 is a longitudinal sectional view taken on the line 4-4 of Figure 3;

Fig. 5 is a transverse sectional view taken on the line 5-5 of Figure 3;

Figures 6 and 8 are sectional views illustrating the hard surfacing material initially formed on the dies;

Figures 7 and 9 are views similar to Figures 6 and 8, respectively, showing the corners removed from the die; and

Figure 10 is a view illustrating removal of the die from the tong jaw.

In the drawings, the letter A designates a pipe tong or gripping device which may be of any suitable construction and which is shown herein merely for the purpose of illustration. The usual tong or gripping device includes a plurality of jaws 10 which are ordinarily pivotally mounted on the body of the tool. Some or all of the gripping jaws 10 are adapted to receive a gripping die B which forms the present invention. The jaw is provided with a dovetail slot 11 which extends vertically on the inner face of the jaw, as illustrated in Figure 2, and the die B is adapted to have a driving fit within the groove.

It is the usual practice to drive the die into position within the groove 11 by means of hammer blows, and when the die is to be removed the same is driven from the groove. Because the tong device is relatively heavy, being usually suspended from cables or flexible lines, it

is not practical to turn the tong so that the die may be" removed by driving the same upwardly. Because .the

groove 11 is relatively narrow, the driving of the die:

from the groove is usually accomplished by means of a chisel or driving rod, indicated at C in Figure 10, this tool being utilized to transmit the hammer blows to the upper end of the die.

The present invention resides in the construction of a die B which has certain advantages over the dies now in general use. As is clearly illustrated in Figures 35, the die B comprises an elongate bar or body section 12, which has a rear or inner wall 13 and a front or outer surface 14, together with longitudinal side walls or surfaces 15. As shown in Figure 5, the side walls 15 are inclined complementary to the dovetail cross-section of the groove 11, while the surface 14 is formed with gripping teeth 16. The particular configuration and arrangement of the teeth 16 are of importance and will be hereinafter described in detail.

The bar or body section 12 has an upper flat end 17 and a lower fiat end 18. The corners which are formed at the intersection of the upper flat end 17 and the inner and outer surfaces 13 and 14 are beveled or inclined as shown at 19; similarly, the corners between the flat end v 17 and the side walls 15 are beveled or inclined as illustrated at 20. In order that the die may be reversible, the corners between the lower flat end 18 and the surfaces 13 and 14 are beveled at 21, while the corners between said lower end and the side walls are also beveled at 22.

The construction of the die and the formation of the beveled corners is clearly shown in Figures 69. The die is initially formed of a relatively soft metallic material which has sharp corners in view of the beveled corners shown in Figures 3 and 4. After formation of the bar and the cutting of the teeth thereon, the bar is heat treated, and this forms a layer of hardened material 23 which completely encompasses the softer core material indicated at 24. The soft core surrounded by the hardened layer is illustrated in Figure 6'. Thereafter, the respective corners 1922 are formed by grinding off the angular corner which was originally provided. In Figure 7 the beveled corners 19 are illustrated, while in Figure 9 the beveled corners 20 are illustrated. It will be evident that the grinding operation removes a portion of the hardened layer 23 and exposes an area which is indicated by 24a of the soft core material. However, the major portion of the hardened layer 23 on the flat ends 17 and 18 remains, and thus the ends of the die have the hardened layer with only the corners exposing the softer material.

The advantages of this construction reside in the fact that the die may be driven into place within the groove 11 of the tong jaw without any substantial chipping of the hardened material. found that when a die having a hardened end with a sharp corner is attempted to be driven into place, the sharp corner tends to chip and thereby create a flying particle hazard. By removing the hardened material from the corners and by exposing some of the softer material at the point 24a, any hammer blows applied to the flat end of the die will not cause a chipping; actually, since the softer material is exposed at point 24a there can be some deformation of the die at this point, and this functions as a shock absorber to the hammer blows. It is thus possible to drive the die into position within the groove without creating an undue hazard.

When the die is to be removed, the hardened layer of material at the end of the die may be engaged by the driving tool or rod C, and since the material is hardened said tool will not deform the end of the die. It has been found that where the end of the die is entirely soft the relatively small tool which is necessary to drive the die out of the groove will result in deforming the die end and will actually cause a spreading thereof within the groove which results in tightly wedging the die into the groove without effecting its removal. However, where the hardened layer remains in the die, the driving tool cannot deform the die end as it can when said die end is In actual practice, it has been 4 soft, and easier removal of the die from the groove may be effected.

The particular construction of the gripping teeth of the die eliminates undue scoring of the pipe being gripped, and the construction of said teeth is clearly shown in Figure 3. In forming the teeth, a plurality of longitudinal tooth elements 25 are first formed in the surface 14 of the die. Each tooth element is substantially conical or triangular shaped in cross-section, with the crest 25a of each tooth extending in a plane parallel to the longitudinal axis of the die bar. The root or valley 25b of each tooth element also extends parallel to the longitudinal axis. After the longitudinal tooth elements 25 are formed, a plurality of V-shaped grooves 26 are cut across the tooth elements at an oblique angle to the longitudinal axis. The grooves 26 are all parallel to each other, as is indicated in Figure 3 and function to divide the tooth elements into a plurality of individual teeth T which are separated by the grooves 26. By observing Figure 3 it will be seen that the teeth T are arranged in longitudinal rows whereby the teeth are aligned in a plane longitudinally of the bar; however, because the grooves 26 are cut at an angle with respect to a plane transversely of the bar the teeth T are staggered or offset with respect to each other in a plane transversely of the bar.

When the die having the teeth formed in the manner described engages the exterior surface of the pipe, it will be evident that the teeth engage the pipe in different plans transversely of the pipe. In other Words, the tooth T of one longitudinal row will engage the pipe at a higher or lower elevation on the pipe than will the teeth of adjacent rows. If there is any slippage of the die upon the pipe surface, the adjacent tooth will not follow in the same path as the preceding tooth but will actually engage the pipe at a different point. Where the teeth are all arranged in rows parallel to a plane transversely of the die, it is evident that each tooth of each transverse roW will engage the same portion of the pipe, and if there is any tendency for one tooth to slip, the next tooth would merely try to grip the portion of the pipe on which slippage occurs. However, where teeth are staggered with respect to each other, any tendency of the die to rotate around the pipe surface will cause the following tooth to engage a different surface than that surface from which the preceding tooth slipped. Actual use has shown that the staggered or offset tooth arrangement reduces slippage to a minimum and prevents undue scoring of the pipe.

From the foregoing, it will be seen that a simple and etficient die for pipe tongs or other similar devices is provided. The arrangement of the teeth on the gripping surface of the die assures an efficient pipe-gripping action, while the end construction of the die makes it possible to drive the die into place and to assure removal of the die by driving it from the groove. As has been noted, the upper and lower ends of the die are formed in exactly the same manner, and by reason of the tooth construction the die is completely reversible so that either end may be considered the upper end.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof, and various changes in the size, shape and materials, as well as in the details of the illustrated construction may be made, within the scope of the appended claims, without departing from the spirit of the invention.

Having described the invention, I claim:

1. A die for a gripping device comprising, a body section in the form of an elongate bar having an inner core of relatively soft metal and having its outer surface heat treated to provide a hardened outer layer surrounding the core, said layer completely encompassing the bar except at the upper corners thereof which corners are beveled and expose the softer material of the core.

2. A die for a gripping device comprising, an elongate metallic bar which is generally rectangular in longitudinal section and which has the corners at the upper end of the bar beveled, the bar being formed of a core of relatively soft material and having all of its outer surface except for the beveled corner areas of a hardened layer which is formed by heat treating said surface.

3. A die for a gripping device comprising, an elongate bar which is generally rectangular in longitudinal section, the central portion of the bar being formed of a relatively soft metallic material and the outer surface of the die being heat treated to provide a hardened outer layer, the corners at one end of the die being ground off to bevel the same and to remove the hardened layer whereby the relatively soft material of the bar is exposed at said corners only.

4. A die for a gripping device comprising, a bar having a flat end and longitudinally extending flat side surfaces, the corners between said flat end and said side surfaces being beveled, said bar having an inner core of relatively soft metallic material which is exposed at the beveled corner portions and having both the fiat end and the flat side surfaces covered with a layer of hardened metal.

5. A die as set forth in claim 1, together with a gripping surface on the body section which surface is formed by gripping teeth which are staggered with respect to each other in a plane transversely of the body.

6. A die as set forth in claim 2, together with gripping teeth on one surface of the bar, said teeth being in alignment with each other in a plane longitudinally of the bar but being staggered or offset relative to each other in a transverse plane.

7. A die as set forth in claim 4, together with gripping teeth formed on one of the longitudinally extending flat sides of the bar, said teeth being disposed in alignment with each other in a plane longitudinally of the bar and being staggered or offset relative to each other in a plane transversely of the bar.

8. A die for a gripping device comprising, an elongate bar having a gripping surface on one longitudinal side thereof, said gripping surface being formed by gripping teeth which are disposed in alignment with each other in a plane longitudinally of the bar and which are staggered a: offset relative to each other in a plane transversely of char.

9. A die for a gripping device comprising, an elongate bar having a gripping surface on one longitudinal side thereof, said gripping surface being formed by gripping teeth which are disposed in alignment with each other in a plane longitudinally of the bar and which are staggered or offset relative to each other in a plane transversely of the bar, each gripping tooth being generally conical in transverse section.

10. A die for a gripping device comprising, an elongate bar having a gripping surface on one longitudinal side thereof, said gripping surface being provided by a plurality of longitudinally extending teeth elements on the bar, and grooves extending across said teeth elements at an oblique angle to a plane longitudinally of the bar to thereby divide the teeth elements into a plurality of indi vidual teeth which are offset in a plane transversely of the bar.

11. A die for a gripping device comprising, an elongate bar having a gripping surface on one longitudinal side thereof, said gripping surface being provided by a plurality of longitudinally extending teeth elements on the bar, and grooves extending across said teeth elements at an oblique angle to a plane longitudinally of the bar to thereby divide the teeth elements into a plurality of individual teeth which are offset in a plane transversely of the bar, each tooth being generally conical in transverse section.

12. A die for a gripping device comprising, an elongate bar having a gripping surface on one longitudinal side thereof, said gripping surface being provided with a plurality of elongate teeth elements which extend in parallel relation to each other on the bar, and grooves extending across said teeth elements at an oblique angle to a plane longitudinally of the bar to thereby divide the teeth elements into a plurality of individual teeth which are offset in a plane transversely of the bar.

References Cited in the file of this patent UNITED STATES PATENTS 2,098,369 Baash Nov. 9, 1937 2,517,366 Wilson Aug. 1, 1950 2,596,880 Weiss May 13, 1952 2,609,720 Barnard Sept. 9, 1952 

